With the spread of smart phones (hereinafter referred to as “smartphones”) and improvements in power saving in wireless communication, a position search service system for detecting for the position of a detection target such as a child, an elderly person or a pet has been proposed which uses a wireless beacon device (hereinafter referred to as a “beacon device”) and smartphones. For example, a system has been proposed in which a target desired to be searched for such as a child is made to carry a power saving wireless beacon device, and smartphones of third parties which smartphones have a search application installed thereon detect the beacon device. In this system, smartphone position information when a smartphone group registered in advance detects a beacon signal may be sent to a user terminal of a protector or the like.
Examples of the related art include Japanese National Publication of International Patent Application No. 2015-528897, Japanese Laid-open Patent Publication No. 2015-103917, and Recruit Sumai Company Ltd. “Starting demonstration tests of child watching service utilizing beacons” (Sep. 2, 2015) URL http://www.recruit-sumai.co.jp/press/150902_SUUMO_mimamoriservice.pdf.